KernelLand/Kernel/arch/x86/vm8086.c

   1 /*
   2  * Acess2 VM8086 Driver
   3  * - By John Hodge (thePowersGang)
   4  */
   5 #define DEBUG   0
   6 #include <acess.h>
   7 #include <vm8086.h>
   8 #include <modules.h>
   9 #include <hal_proc.h>
  10 #include <semaphore.h>
  11
  12 // === CONSTANTS ===
  13 #define TRACE_EMU       0
  14
  15 #define VM8086_MAGIC_CS 0xFFFF
  16 #define VM8086_MAGIC_IP 0x0010
  17 #define VM8086_STACK_SEG        0x9F00
  18 #define VM8086_STACK_OFS        0x0AFE
  19 enum eVM8086_Opcodes
  20 {
  21         VM8086_OP_PUSHF   = 0x9C,
  22         VM8086_OP_POPF    = 0x9D,
  23         VM8086_OP_INT_I   = 0xCD,
  24         VM8086_OP_IRET    = 0xCF,
  25         VM8086_OP_IN_AD   = 0xEC,
  26         VM8086_OP_IN_ADX  = 0xED,
  27         VM8086_OP_OUT_AD  = 0xEE,
  28         VM8086_OP_OUT_ADX = 0xEF
  29 };
  30 #define VM8086_PAGES_PER_INST   4
  31
  32 #define VM8086_BLOCKSIZE        128
  33 #define VM8086_BLOCKCOUNT       ((0x9F000-0x10000)/VM8086_BLOCKSIZE)
  34
  35 // === TYPES ===
  36 struct sVM8086_InternalData
  37 {
  38         struct {
  39                 Uint32  Bitmap; // 32 sections = 128 byte blocks
  40                 tVAddr  VirtBase;
  41                 tPAddr  PhysAddr;
  42         }       AllocatedPages[VM8086_PAGES_PER_INST];
  43 };
  44
  45 // === PROTOTYPES ===
  46  int    VM8086_Install(char **Arguments);
  47 void    VM8086_GPF(tRegs *Regs);
  48 //tVM8086       *VM8086_Init(void);
  49
  50 // === GLOBALS ===
  51 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  52 tMutex  glVM8086_Process;
  53 tSemaphore      gVM8086_TaskComplete;
  54 tSemaphore      gVM8086_TasksToDo;
  55 tPID    gVM8086_WorkerPID;
  56 tTID    gVM8086_CallingThread;
  57 tVM8086 volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
  58 Uint32  gaVM8086_MemBitmap[VM8086_BLOCKCOUNT/32];
  59  int    gbVM8086_ShadowIF = 0;
  60
  61 // === FUNCTIONS ===
  62 int VM8086_Install(char **Arguments)
  63 {
  64         tPID    pid;
  65
  66         Semaphore_Init(&gVM8086_TasksToDo, 0, 10, "VM8086", "TasksToDo");
  67
  68         // Lock to avoid race conditions
  69         Mutex_Acquire( &glVM8086_Process );
  70
  71         // Create BIOS Call process
  72         pid = Proc_Clone(CLONE_VM);
  73         Log_Debug("VM8086", "pid = %i", pid);
  74         if(pid == -1)
  75         {
  76                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  77                 return MODULE_ERR_MISC;
  78         }
  79         if(pid == 0)
  80         {
  81                 Uint    * volatile stacksetup;  // Initialising Stack
  82                 Uint16  * volatile rmstack;     // Real Mode Stack
  83                  int    i;
  84
  85                 Log_Debug("VM8086", "Initialising worker");
  86
  87                 // Set Image Name
  88                 Threads_SetName("VM8086");
  89
  90                 // Map ROM Area
  91                 for(i=0xA0;i<0x100;i++) {
  92                         MM_Map( i * 0x1000, i * 0x1000 );
  93                 }
  94                 MM_Map( 0, 0 ); // IVT / BDA
  95                 // Map (but allow allocation) of 0x1000 - 0x9F000
  96                 // - So much hack, it isn't funny
  97                 // TODO: Remove this and replce with something less hacky
  98                 for(i=1;i<0x9F;i++) {
  99                         MM_Map( i * 0x1000, i * 0x1000 );
 100                         while(MM_GetRefCount(i*0x1000))
 101                                 MM_DerefPhys( i * 0x1000 );
 102                 }
 103                 MM_Map( 0x9F000, 0x9F000 );     // Stack / EBDA
 104                 // System Stack / Stub
 105                 if( MM_Allocate( 0x100000 ) == 0 ) {
 106                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
 107                         gVM8086_WorkerPID = 0;
 108                         Threads_Exit(0, 1);
 109                 }
 110
 111                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
 112                 *(Uint8*)(0x100001) = 0x07;     // POP ES
 113                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
 114                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
 115
 116                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
 117                 rmstack--;      *rmstack = 0xFFFF;      //CS
 118                 rmstack--;      *rmstack = 0x0010;      //IP
 119
 120                 // Setup Stack
 121                 stacksetup = (Uint*)0x101000;
 122                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 123                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 124                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 125                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 126                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 127                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 128                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 129                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 130                 stacksetup--;   *stacksetup = 0x10;     // IP
 131                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 132                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 133                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 134                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 135                 stacksetup--;   *stacksetup = 0x5454;   // SP
 136                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 137                 stacksetup--;   *stacksetup = 0x5151;   // SI
 138                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 139                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 140                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 141                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 142                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 143                 __asm__ __volatile__ (
 144                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 145                 "pop %%gs;\n\t"
 146                 "pop %%fs;\n\t"
 147                 "pop %%es;\n\t"
 148                 "pop %%ds;\n\t"
 149                 "popa;\n\t"
 150                 "iret;\n\t" : : "a" (stacksetup));
 151                 for(;;);        // Shouldn't be reached
 152         }
 153
 154         gVM8086_WorkerPID = pid;
 155
 156         // It's released when the GPF fires
 157         Mutex_Acquire( &glVM8086_Process );
 158         Mutex_Release( &glVM8086_Process );
 159
 160         // Worker killed itself
 161         if( gVM8086_WorkerPID != pid ) {
 162                 return MODULE_ERR_MISC;
 163         }
 164
 165         return MODULE_ERR_OK;
 166 }
 167
 168 void VM8086_GPF(tRegs *Regs)
 169 {
 170         Uint8   opcode;
 171         Uint16  newcs, newip;
 172
 173 //      Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 174
 175         LOG("VM8086 GPF at %04x:%04x", Regs->cs, Regs->eip);
 176
 177         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 178         && Threads_GetPID() == gVM8086_WorkerPID)
 179         {
 180                 if( gpVM8086_State == (void*)-1 ) {
 181                         Log_Log("VM8086", "Worker thread ready and waiting");
 182                         gpVM8086_State = NULL;
 183                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 184                 }
 185 //              Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 186 //                      gpVM8086_State, gVM8086_CallingThread);
 187                 if( gpVM8086_State ) {
 188                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 189                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 190                         gpVM8086_State->BP = Regs->ebp;
 191                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 192                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 193                         gpVM8086_State = NULL;
 194                         // Wake the caller
 195                         Semaphore_Signal(&gVM8086_TaskComplete, 1);
 196                 }
 197
 198                 //Log_Log("VM8086", "Waiting for something to do");
 199                 __asm__ __volatile__ ("sti");
 200                 Semaphore_Wait(&gVM8086_TasksToDo, 1);
 201
 202                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 203                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 204                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 205                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 206                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 207                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 208                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 209
 210                 // Set Registers
 211                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 212                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 213                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 214                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 215                 Regs->ebp = gpVM8086_State->BP;
 216                 Regs->ds = 0x23;        Regs->es = 0x23;
 217                 Regs->fs = 0x23;        Regs->gs = 0x23;
 218                 return ;
 219         }
 220
 221         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 222         Regs->eip ++;
 223         switch(opcode)
 224         {
 225         case VM8086_OP_PUSHF:   //PUSHF
 226                 Regs->esp -= 2;
 227                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 228                 if( gbVM8086_ShadowIF )
 229                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) |= 0x200;
 230                 else
 231                         *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) &= ~0x200;
 232                 #if TRACE_EMU
 233                 Log_Debug("VM8086", "%04x:%04x Emulated PUSHF (value 0x%x)",
 234                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 235                 #endif
 236                 break;
 237         case VM8086_OP_POPF:    //POPF
 238                 // Changing IF is not allowed
 239                 Regs->eflags &= 0xFFFF0202;
 240                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );
 241                 gbVM8086_ShadowIF = !!(*(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0x200);
 242                 Regs->esp += 2;
 243                 #if TRACE_EMU
 244                 Log_Debug("VM8086", "%04x:%04x Emulated POPF (new value 0x%x)",
 245                         Regs->cs, Regs->eip-1, Regs->eflags & 0xFFFF);
 246                 #endif
 247                 break;
 248
 249         case VM8086_OP_INT_I:   //INT imm8
 250                 {
 251                  int    id;
 252                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 253                 Regs->eip ++;
 254
 255                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 256                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 257
 258                 newcs = *(Uint16*)(4*id + 2);
 259                 newip = *(Uint16*)(4*id);
 260                 #if TRACE_EMU
 261                 Log_Debug("VM8086", "%04x:%04x Emulated INT 0x%x (%04x:%04x) - AX=%04x,BX=%04x",
 262                         Regs->cs, Regs->eip-2, id, newcs, newip, Regs->eax, Regs->ebx);
 263                 #endif
 264                 Regs->cs = newcs;
 265                 Regs->eip = newip;
 266                 }
 267                 break;
 268
 269         case VM8086_OP_IRET:    //IRET
 270                 newip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 271                 newcs = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ); Regs->esp += 2;
 272                 #if TRACE_EMU
 273                 Log_Debug("VM8086", "%04x:%04x IRET to %04x:%04x",
 274                         Regs->cs, Regs->eip-1, newcs, newip);
 275                 #endif
 276                 Regs->cs = newcs;
 277                 Regs->eip = newip;
 278                 break;
 279
 280
 281         case VM8086_OP_IN_AD:   //IN AL, DX
 282                 Regs->eax &= 0xFFFFFF00;
 283                 Regs->eax |= inb(Regs->edx&0xFFFF);
 284                 #if TRACE_EMU
 285                 Log_Debug("VM8086", "%04x:%04x Emulated IN AL, DX (Port 0x%x [Val 0x%02x])",
 286                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 287                 #endif
 288                 break;
 289         case VM8086_OP_IN_ADX:  //IN AX, DX
 290                 Regs->eax &= 0xFFFF0000;
 291                 Regs->eax |= inw(Regs->edx&0xFFFF);
 292                 #if TRACE_EMU
 293                 Log_Debug("VM8086", "%04x:%04x Emulated IN AX, DX (Port 0x%x [Val 0x%04x])",
 294                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 295                 #endif
 296                 break;
 297
 298         case VM8086_OP_OUT_AD:  //OUT DX, AL
 299                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 300                 #if TRACE_EMU
 301                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AL (*0x%04x = 0x%02x)",
 302                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFF);
 303                 #endif
 304                 break;
 305         case VM8086_OP_OUT_ADX: //OUT DX, AX
 306                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 307                 #if TRACE_EMU
 308                 Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, AX (*0x%04x = 0x%04x)",
 309                         Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 310                 #endif
 311                 break;
 312
 313         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 314         case 0xFA:      //CLI
 315                 #if TRACE_EMU
 316                 Log_Debug("VM8086", "%04x:%04x Ignored CLI",
 317                         Regs->cs, Regs->eip);
 318                 #endif
 319                 gbVM8086_ShadowIF = 0;
 320                 break;
 321         case 0xFB:      //STI
 322                 #if TRACE_EMU
 323                 Log_Debug("VM8086", "%04x:%04x Ignored STI",
 324                         Regs->cs, Regs->eip);
 325                 #endif
 326                 gbVM8086_ShadowIF = 1;
 327                 break;
 328
 329         case 0x66:
 330                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 331                 Regs->eip ++;
 332                 switch( opcode )
 333                 {
 334                 case VM8086_OP_IN_ADX:  //IN AX, DX
 335                         Regs->eax = ind(Regs->edx&0xFFFF);
 336                         #if TRACE_EMU
 337                         Log_Debug("VM8086", "%04x:%04x Emulated IN EAX, DX (Port 0x%x [Val 0x%08x])",
 338                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 339                         #endif
 340                         break;
 341                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 342                         outd(Regs->edx&0xFFFF, Regs->eax);
 343                         #if TRACE_EMU
 344                         Log_Debug("VM8086", "%04x:%04x Emulated OUT DX, EAX (*0x%04x = 0x%08x)",
 345                                 Regs->cs, Regs->eip-1, Regs->edx&0xFFFF, Regs->eax);
 346                         #endif
 347                         break;
 348                 default:
 349                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 350                                 Regs->cs, Regs->eip-2,
 351                                 opcode
 352                                 );
 353                         // Force an end to the call
 354                         Regs->cs = VM8086_MAGIC_CS;
 355                         Regs->eip = VM8086_MAGIC_IP;
 356                         break;
 357                 }
 358                 break;
 359
 360         default:
 361                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 362                         opcode, Regs->cs, Regs->eip-1);
 363                 // Force an end to the call
 364                 Regs->cs = VM8086_MAGIC_CS;
 365                 Regs->eip = VM8086_MAGIC_IP;
 366                 break;
 367         }
 368 }
 369
 370 /**
 371  * \brief Create an instance of the VM8086 Emulator
 372  */
 373 tVM8086 *VM8086_Init(void)
 374 {
 375         tVM8086 *ret;
 376         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 377         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 378         return ret;
 379 }
 380
 381 void VM8086_Free(tVM8086 *State)
 382 {
 383          int    i;
 384         for( i = VM8086_PAGES_PER_INST; i --; )
 385                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 386         free(State);
 387 }
 388
 389 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 390 {
 391          int    i, j, base = 0;
 392          int    nBlocks, rem;
 393
 394         Size = (Size + 127) & ~127;
 395         nBlocks = Size / 128;
 396
 397         if(Size > 4096) return NULL;
 398
 399         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 400         {
 401                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 402
 403
 404                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 405
 406                 rem = nBlocks;
 407                 base = 0;
 408                 // Scan the bitmap for a free block
 409                 for( j = 0; j < 32; j++ ) {
 410                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 411                                 base = j+1;
 412                                 rem = nBlocks;
 413                         }
 414
 415                         rem --;
 416                         if(rem == 0)    // Goodie, there's a gap
 417                         {
 418                                 for( j = 0; j < nBlocks; j++ )
 419                                         State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 420                                 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 421                                 *Offset = 0;
 422                                 LOG("Allocated at #%i,%04x", i, base*128);
 423                                 LOG(" - %x:%x", *Segment, *Offset);
 424                                 return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 425                         }
 426                 }
 427         }
 428
 429         // No pages with free space?, allocate a new one
 430         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 431         {
 432                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 433         }
 434         // Darn, we can't allocate any more
 435         if( i == VM8086_PAGES_PER_INST ) {
 436                 Log_Warning("VM8086", "Out of pages in %p", State);
 437                 return NULL;
 438         }
 439
 440         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 441                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 442         State->Internal->AllocatedPages[i].Bitmap = 0;
 443
 444         for( j = 0; j < nBlocks; j++ )
 445                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 446         LOG("AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 447         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 448         *Offset = 0;
 449         LOG(" - %x:%x", *Segment, *Offset);
 450         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 451 }
 452
 453 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 454 {
 455         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 456 }
 457
 458 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 459 {
 460         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 461         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 462
 463 //      Log_Debug("VM8086", "Software interrupt %i to %04x:%04x", Interrupt, State->CS, State->IP);
 464
 465         Mutex_Acquire( &glVM8086_Process );
 466
 467         gpVM8086_State = State;
 468         gVM8086_CallingThread = Threads_GetTID();
 469         Semaphore_Signal(&gVM8086_TasksToDo, 1);
 470
 471         Semaphore_Wait(&gVM8086_TaskComplete, 1);
 472
 473         Mutex_Release( &glVM8086_Process );
 474 }